Wheels, Tires:VSC problems?

QUESTION:
Can smaller wheel and tire size effect the "VSC" Vehicle Stability Control system?
:?:
I have noticed that my sisters xB (which now has smaller tires) is acting weird.
50% of the time the VSC doesn't work when sliding in the snow.
I can take my xB (which has taller tires) though the same course and the VSC works great.
She took her xB to the dealer and they checked the computer systems.
They said everything was working fine but that the smaller tires may be effecting the VSC and ABS.


Any ideas?



DETAILS & DATA:

My sister I both have 2004 Scion xB's
Because we live in NY, we have switched to snow tires.
Both xB's have now have Bridgestone Blizzack tires that came from another vehicle.

OEM tire size:
2004 Scion xB
185/60-15

Green xB (My Rally xB)
195/60/15 (1 year old tires from a 2000 Toyota Celica)
% Difference: + 1.99 (bigger)

Red xB (Sisters)
195/60/14 (1.5 year old tires & aluminum wheels from a 1996 VW Jetta)
% Difference: -2.22 (smaller)


Tire Size Calculator:
http://pw1.netcom.com/~sgalaba/tiresize.htm

 

i would not see why it would affect it but maybe it is thats just my .02 cents

 

Bump.

 

VSC only reduce the chance of skidding. Sometimes, it just fails to save us altogether, if you push the car to the limit.. So you probably feel like it works better in your car, due to bigger wheele (probably lower profile)... you get less body roll ... ?

 

The difference in tire size is small enough that it shouldn't matter.

The simple way to verify that it's not the tires is to swap them from your xB to hers. If it's still not working right, take it back to the dealer.

 

My tires use the OEM 15" wheels (rims) but have wider and taller rubber (tires) on them.
They are not low-profile. There is no change in body lean.
The ABS and VSC works great each and every time with my xB.
:D
I guess my question should be this:
What are technical specs (tolerances) for the speed sensors
in the anti-lock breaking systems?
Based on a comparison between:
My xB (taller tires = +1.99%)
and
My sisters xB (smaller tires = -2.22%)

It seems that the ABS / VSC computer will accept an increase
in tire diameter but not a decrease in tire diameter.

Any Toyota / Scion mechanics here that can verify this?
:?: :?: :?:

 

Bump.
Any Toyota / Scion mechanics here that can verify this?
:?:

 

Bump.
:?:

 

the tire size will make it act diffrently

take a rx8 and put on skinnier tires,diffrent brand ,etc. and take it in a corner, it will act diffrently or even just a diffrent brand, go from michelin pilots to a goodyear highway tire and you will feel a diffrence

VSC is only as good as the tires on the car and why the hell would you mess around with tire size like that? you should be keeping it about the same diameter, thats what tire size calculators are for.... throwing on any tire size and making it about 2% diffrent + or - is just plain idiotic

 

No more "idiotic" than putting on 18" wheels, lowering springs, or wider tires like a lot of other people have already done.
I guess if you have read the other threads you would have know that.


BTW:
The OEM tires are back on my sisters car
and now the VSC works normally.


Conclusion:
I believe that computer can compensate for slightly bigger tires, not smaller.
I was hoping for some actual technical specs from a Toyota / Scion tech to confirm this... not just "comments" from someone being sarcastic.